2009-08-08 09:04:08

by Johannes Berg

Subject: [PATCH] cfg80211: fix locking for SIWFREQ

"cfg80211: validate channel settings across interfaces"
contained a locking bug -- in the managed-mode SIWFREQ
call it would end up running into a lock recursion.

This fixes it by not checking that particular interface
for a channel that it needs to stay on, which is as it
should be as that's the interface we're setting the
channel for.

Reported-by: Reinette Chatre <[email protected]>
Reported-by: Kalle Valo <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>
---
net/wireless/chan.c | 3 ++-
net/wireless/core.h | 1 +
net/wireless/nl80211.c | 2 +-
net/wireless/wext-compat.c | 2 +-
net/wireless/wext-sme.c | 2 +-
5 files changed, 6 insertions(+), 4 deletions(-)

--- wireless-testing.orig/net/wireless/chan.c 2009-08-08 10:53:52.000000000 +0200
+++ wireless-testing/net/wireless/chan.c 2009-08-08 10:54:10.000000000 +0200
@@ -42,13 +42,14 @@ rdev_fixed_channel(struct cfg80211_regis
}

int rdev_set_freq(struct cfg80211_registered_device *rdev,
+ struct wireless_dev *for_wdev,
int freq, enum nl80211_channel_type channel_type)
{
struct ieee80211_channel *chan;
struct ieee80211_sta_ht_cap *ht_cap;
int result;

- if (rdev_fixed_channel(rdev, NULL))
+ if (rdev_fixed_channel(rdev, for_wdev))
return -EBUSY;

if (!rdev->ops->set_channel)
--- wireless-testing.orig/net/wireless/core.h 2009-08-08 10:54:29.000000000 +0200
+++ wireless-testing/net/wireless/core.h 2009-08-08 10:54:37.000000000 +0200
@@ -374,6 +374,7 @@ struct ieee80211_channel *
rdev_fixed_channel(struct cfg80211_registered_device *rdev,
struct wireless_dev *for_wdev);
int rdev_set_freq(struct cfg80211_registered_device *rdev,
+ struct wireless_dev *for_wdev,
int freq, enum nl80211_channel_type channel_type);

#endif /* __NET_WIRELESS_CORE_H */
--- wireless-testing.orig/net/wireless/nl80211.c 2009-08-08 10:54:51.000000000 +0200
+++ wireless-testing/net/wireless/nl80211.c 2009-08-08 10:54:58.000000000 +0200
@@ -721,7 +721,7 @@ static int nl80211_set_wiphy(struct sk_b
freq = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]);

mutex_lock(&rdev->devlist_mtx);
- result = rdev_set_freq(rdev, freq, channel_type);
+ result = rdev_set_freq(rdev, NULL, freq, channel_type);
mutex_unlock(&rdev->devlist_mtx);
if (result)
goto bad_res;
--- wireless-testing.orig/net/wireless/wext-compat.c 2009-08-08 10:54:52.000000000 +0200
+++ wireless-testing/net/wireless/wext-compat.c 2009-08-08 10:55:04.000000000 +0200
@@ -766,7 +766,7 @@ int cfg80211_wext_siwfreq(struct net_dev
if (freq == 0)
return -EINVAL;
mutex_lock(&rdev->devlist_mtx);
- err = rdev_set_freq(rdev, freq, NL80211_CHAN_NO_HT);
+ err = rdev_set_freq(rdev, NULL, freq, NL80211_CHAN_NO_HT);
mutex_unlock(&rdev->devlist_mtx);
return err;
}
--- wireless-testing.orig/net/wireless/wext-sme.c 2009-08-08 10:54:52.000000000 +0200
+++ wireless-testing/net/wireless/wext-sme.c 2009-08-08 10:55:08.000000000 +0200
@@ -106,7 +106,7 @@ int cfg80211_mgd_wext_siwfreq(struct net

/* SSID is not set, we just want to switch channel */
if (chan && !wdev->wext.connect.ssid_len) {
- err = rdev_set_freq(rdev, freq, NL80211_CHAN_NO_HT);
+ err = rdev_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
goto out;
}

2009-08-09 02:56:54

by Larry Finger

Subject: Re: [PATCH] cfg80211: fix locking for SIWFREQ

Johannes Berg wrote:
> "cfg80211: validate channel settings across interfaces"
> contained a locking bug -- in the managed-mode SIWFREQ
> call it would end up running into a lock recursion.
>
> This fixes it by not checking that particular interface
> for a channel that it needs to stay on, which is as it
> should be as that's the interface we're setting the
> channel for.
>
> Reported-by: Reinette Chatre <[email protected]>
> Reported-by: Kalle Valo <[email protected]>
> Signed-off-by: Johannes Berg <[email protected]>
> ---

This patch also fixes the problem that I had.

Larry

2009-08-10 16:55:08

by Reinette Chatre

Subject: Re: [PATCH] cfg80211: fix locking for SIWFREQ

On Sat, 2009-08-08 at 02:03 -0700, Johannes Berg wrote:
> "cfg80211: validate channel settings across interfaces"
> contained a locking bug -- in the managed-mode SIWFREQ
> call it would end up running into a lock recursion.
>
> This fixes it by not checking that particular interface
> for a channel that it needs to stay on, which is as it
> should be as that's the interface we're setting the
> channel for.
>
> Reported-by: Reinette Chatre <[email protected]>
> Reported-by: Kalle Valo <[email protected]>
> Signed-off-by: Johannes Berg <[email protected]>

Not sure if this is still needed, but for completeness:

Tested-by: Reinette Chatre <[email protected]>

Thank you very much

Reinette

2009-08-08 09:41:17

by Kalle Valo

Subject: Re: [PATCH] cfg80211: fix locking for SIWFREQ

Johannes Berg <[email protected]> writes:

> "cfg80211: validate channel settings across interfaces"
> contained a locking bug -- in the managed-mode SIWFREQ
> call it would end up running into a lock recursion.
>
> This fixes it by not checking that particular interface
> for a channel that it needs to stay on, which is as it
> should be as that's the interface we're setting the
> channel for.

Thanks, this fixes the problem I reported.

> Reported-by: Reinette Chatre <[email protected]>
> Reported-by: Kalle Valo <[email protected]>
> Signed-off-by: Johannes Berg <[email protected]>

Tested-by: Kalle Valo <[email protected]>

--
Kalle Valo